Wedge shaped suture anchor and method of implantation

ABSTRACT

A suture anchor is described which in one form may be easily fabricated from extruded material by angular cuts and bore holes which provide an offset pulling force to the suture. In an alternate and preferred embodiment the suture anchor is injection molded having an annular displaced corner and abutment wall which act to seat the suture anchor firmly within a bore hole. Novel application means are also disclosed which hold the suture anchor on a frangible shaft for insertion and upon completion of the insertion permit fracture of the frangible portion and removal of the instrument. In another form of the invention, the suture anchor comprises a substantially wedge-shaped body having a smaller distal end and a larger proximal end, means thereon for retaining a suture, and means thereon for releasable connection to an inserter shaft; a boundary surface and a plow surface of the body intersecting to form a biting edge at the proximal end of the body; and the boundary surface and an abutment surface of the body intersecting to form a cam surface at the proximal end of the body; and the biting edge being adapted to be in engagement with a first wall portion of a bore in a bone and the cam surface being adapted to be in engagement with a second wall portion of the bore opposed to the first wall portion; wherein tension on the inserter shaft is operable to move the cam portion along the bore second wall portion and rotate the body in the bore such that the biting edge bites into the bore first wall portion to lock the body in the bore.

This is a continuation of prior U.S. patent application Ser. No.10/782,344, filed Feb. 19, 2004 by Jack S. Pedlick, Thu Anh Le, JohnDiGiovanni, Dennis D. Jamiolkowski, and Mark J. Suseck for WEDGE SHAPEDSUTURE ANCHOR AND METHOD OF IMPLANTATION, which in turn is acontinuation of U.S. patent application Ser. No. 09/923,996, filed Aug.7, 2001 now U.S. Pat. No. 6,726,707 by Jack S. Pedlick, Thu Anh Le, JohnDiGiovanni, Dennis D. Jamiolkowski, and Mark J. Suseck for WEDGE SHAPEDSUTURE ANCHOR AND METHOD OF IMPLANTATION, which in turn is acontinuation of U.S. patent application Ser. No. 09/412,903, filed Oct.5, 1999 now U.S. Pat. No. 6,270,518 by Jack S. Pedlick, Thu Anh Le, JohnDiGiovanni, Dennis D. Jamiolkowski, and Mark J. Suseck for WEDGE SHAPEDSUTURE ANCHOR AND METHOD OF IMPLANTATION, which in turn is acontinuation of U.S. patent application Ser. No. 08/630,389, filed Apr.10, 1996 now U.S. Pat. No. 5,961,538 by Jack S. Pedlick, Thu Anh Le,John DiGiovanni, Dennis D. Jamiolkowski, and Mark J. Suseck for WEDGESHAPED SUTURE ANCHOR AND METHOD OF IMPLANTATION, which patentapplications are hereby incorporated herein by reference.

TECHNICAL FIELD

The field of art to which this invention relates is surgical implementsand more specifically suture anchors for anchoring suture material tobone.

BACKGROUND ART

As the treatment of injuries to joints and soft tissue has progressed inthe orthopaedic medical arts, there has been a need for medical deviceswhich can be used to attach tendons, ligaments and other soft tissue tobone. When surgically repairing an injured joint, for example, it isoften preferable to restore the joint by reattaching the damaged softtissues rather than replacing them with an artificial material. Suchrestorations typically require the attachment of soft tissue such asligaments and tendons to bone.

An increase in the incidence of injuries to joints involving soft tissuehas been observed. This increased incidence may be due, at least inpart, to an increase in participation by the public in various physicalactivities such as sports and other recreational activities. These typesof activities may increase the loads and stress placed upon joints,sometimes resulting in joint injuries with corresponding damage toassociated soft tissue. In 1991, for example, there were approximately560,000 surgical procedures performed in the United States in which softtissue was attached to a bone in various joints including the shoulder,hip and knee.

One conventional orthopaedic procedure for reattaching soft tissue tobone is performed by initially drilling holes or tunnels atpredetermined locations through a bone in the vicinity of a joint. Then,the surgeon approximates soft tissue to the surface of the bone usingsutures threaded through these holes or tunnels. This method, althougheffective, is a time consuming procedure resulting in the generation ofnumerous bone tunnels. A known complication of drilling tunnels acrossbone is that nerves and other soft tissue structures may be injured bythe drill bit or orthopaedic pin as it exits the far side of the bone.Also, it is anatomically very difficult to reach and/or secure asuture/wire that has been passed through a tunnel. When securing thesuture or wire on the far side of the bone, nerves and soft tissues canbecome entrapped and damaged.

In order to overcome some of the problems associated with the use of theconventional bone tunnel procedures, suture anchors have been developedand are frequently used to attach soft tissue to bone. A suture anchoris an orthopaedic, medical device which is typically implanted into acavity drilled into a bone. Although less frequently, these devices havealso been referred to as bone anchors. The cavity is typically referredto as a bore hole and usually does not extend through the bone. Thistype of bore hole is typically referred to as a “blind hole”. The borehole is typically drilled through the outer cortex layer of the bonehole by a variety of mechanisms including friction fit, barbs which areforced into the cancellous layer of bone, etc. Suture anchors are knownto have many advantages including reduced bone trauma, simplifiedapplication procedures, and decreased likelihood of suture failure dueto abrasion on bone. Suture anchors may be used in the Bankart shoulderreconstruction for repairing the glenohumeral ligament and may also beused in surgical procedures such as rotator cuff repair and hipreplacement. Also, such anchors may be used in repair of tendon tears bydirect attachment of tendon to bone.

Suture anchors typically have at least one suture attached. This may beby means of a hole or opening for receiving the suture(s). At least oneend and typically both ends of the suture strand extend out from thebore hole and are used to attach soft tissue. The suture anchorspresently described in the art may be made of absorbable materials whichabsorb over time, or they may be made from various non-absorbable,biocompatible materials. Although most suture anchors described in theart are made from non-absorbable materials, the use of absorbable sutureanchors may result in fewer complications since the suture anchor isabsorbed and replaced by bone over time. In addition, the use ofabsorbable suture anchors may reduce the likelihood of damage to localjoints caused by anchor migration.

Although suture anchors for attaching soft tissue to bone are availablefor use by the orthopaedic surgeon, there is a constant need in this artfor novel suture anchors having improved performance characteristics.

SUMMARY OF THE INVENTION

The device of the present invention calls for an implantable apparatusfor wedging within an opening formed within a bone. The apparatuscomprises a body which defines a perimeter and said perimeter definingat least one biting edge. A hole is defined by the body through which asuture is received for attachment through the device to the bone. Thehole defined by the body may be nearer to one side of the perimeter inorder to provide an imbalance of force to increase rotation of thedevice during the implantation procedure. The body in cross-section mayhave a perimeter which is substantially in the shape of a triangle,trapezoid or parallelogram. In this way the body may have two slideswhich diverge in a direction away from said hole, such that the rotationcauses an edge formed by one of such sides to bite into the softcancellous layer of the bone. In order to better distribute the forcesacting on the device, the sides may be rounded so that the rounded edgewill match with the size of the bore hole provided in the bone. In thisway, maximum contact of the edge with the side of the hole in the boneis provided.

The edge may be formed by the intersection of planar or rounded sides ora combination of planar and rounded sides in order to optimize thebiting action of the edge. The edge may also be provided with a singleengaging tooth or a plurality of engaging teeth in order to improve theholding power, biting and/or placement of the device. The device may betriangular in shape and thus formed by three mutually adjacent sides.

The apparatus may further include a thin longitudinal stem portion whichextends from the body. This stem portion is preferably detachable fromthe body and may be integral and formed with the body out of the samematerial and provided with a frangible portion or may be formedseparately and fitted to the body.

The body may be made of any medical grade material and the stem may bemade of a different medical grade material. The body and stem may bejoined by a frangible portion which could be formed, for example, by twointersecting web portions in order to provide stability to the deviceduring insertion while still providing the weakness necessary forfracture of the area.

The stem may be provided with a protrusion which mates with animplantation device in order to position the stem within theimplantation device at an optimum position.

The body may be made of bioabsorbable material, a biocompatible metal,or a medical grade polymer for example. The body may be of a medicalgrade metal material and the stem made of a bioabsorbable polymer suchthat after fraction the anchor stays implanted but the stem portionremaining after fracture is absorbed by the body.

The invention includes a method of implanting a device for holdingmaterial in the bone which comprises accessing the bone and forming anopening therein for receipt of the device. The device is then gripped bya stem which extends from the device and is inserted into the opening bygripping such a stem. The stem is then detached from the device and thedevice is rotated in order to wedge within the opening formed in thebone.

The separation of the stem from the device may include either breaking aportion of the stem or device in order to separate the stem and deviceor separating the stem via a snap fit, interference fit, or otherattachment mechanism.

The insertion device may include a stabilizing portion to preventexcessive premature rotation of the device and thus prevent prematurefracture of any frangible portion of the stem. This however is notnecessary in the method where the device is attached to the stem throughan interference or frictional fit and the stem is merely removed from anopening in the device during the method of implantation.

In another form of the invention, the suture anchor can comprise asubstantially wedge-shaped body having a smaller distal end and a largerproximal end, means thereon for retaining a suture, and means thereonfor releasable connection to an inserter shaft; a boundary surface and aplow surface of the body intersecting to form a biting edge at theproximal end of the body; and the boundary surface and an abutmentsurface of the body intersecting to form a cam surface at the proximalend of the body; and the biting edge being adapted to be in engagementwith a first wall portion of the bore and the cam surface being adaptedto be in engagement with a second wall portion of the bore opposed tothe first wall portion; wherein tension on the inserter shaft isoperable to move the cam portion along the bore second wall portion androtate the body in the bore such that the biting edge bites into thebore first wall portion to lock the body in the bore.

And in another form of the invention, the suture anchor can comprise asubstantially wedge-shaped body having a smaller distal end and a largerproximal end, the body defining a hole therethrough for retaining asuture, and the body having means thereon for releasable connection toan inserter shaft; the body having first and second opposite andparallel planar sides; the hole extending from the first side to thesecond side; each of the sides being provided with a rounded entrywayleading to the hole, such that the hole is devoid of edges against whichthe suture can impinge.

In still another form of the invention, the suture anchor can comprise asubstantially wedge-shaped body having a smaller distal end and largerproximal end, means thereon for retaining a suture, and means thereonfor releasable connection to an inserter shaft; the body distal endbeing of rounded configuration; a plow surface of the body being ofrounded configuration in plan view; an abutment surface of the bodyopposite from the plow surface being of rounded configuration in planview; and the abutment surface and a boundary surface of the bodyintersecting to form, in side elevational view, a rounded configuration;the rounded configurations being operable to guide entry of the bodyinto the bore in the bone and to center the body in the bore.

And in yet another form of the invention, the suture anchor can comprisea substantially wedge-shaped body having a smaller distal end and alarger proximal end, the body defining a hole therethrough for retaininga suture, and the body having means thereon for releasable connection toan inserter shaft; the hole being substantially elliptical in width-wisecross-section and having a major axis substantially normal to a minoraxis; the major axis being aligned with a selected region of the body todirect stress from the suture toward the selected region of the body.

In another form of the invention, the suture anchor can comprise asubstantially wedge-shaped body having a smaller distal end and a largerproximal end, the body defining a hole therethrough for retaining asuture, and the body having means thereon for releasable connection toan inserter shaft; the body having first and second opposite sides; thehole extending from the first side to the second side; each of the sidesbeing provided with a pathway extending from the hole to a boundarysurface of the body, the pathway extending into the side of the bodyfurther than the diameter of the suture, such that the suture in thehole extends through the pathways and is disposed in the pathwaysremoved from outer surfaces of the body first and second sides.

And in another form of the invention, the suture anchor can comprise asubstantially wedge-shaped body having a smaller distal end and a largerproximal end, the body having means thereon for retaining a suture, anda boundary surface having means therein for releasable connection to aninserter shaft; the means for releasable connection to an inserter shaftcomprising a smooth-walled counterbore in the boundary surface, and asecond bore in a bottom of the counterbore, the second bore beingadapted to receive a threaded end portion of the inserter shaft and tobe threadedly engaged thereby, and the counterbore being adapted toreceive a cylindrically-shaped flexible tip portion of the insertershaft; wherein flexing of the inserter shaft tip portion is permitted bythe counterbore substantially without disturbing the engagement of thethreaded end portion of the inserter shaft with the second bore.

The invention also comprises an installation tool for placing a sutureanchor and a suture attached thereto in a bore in a bone, the toolcomprising an elongated shroud having therein an internal opening; aninserter shaft slidably disposed in the internal opening; the sutureanchor being releasably connected to a distal end of the inserter shaft;the shroud being of elastomeric material and configured to form firstand second channels on opposite sides of the internal opening andadapted each to retain a portion of the suture attached to the anchorand extending proximally therefrom; each of the channels being formedsuch that a first portion of the channel at an outer surface of theshroud is narrower than a second portion of the channel spaced from theshroud outer surface; the suture portions being removable from thechannel second portions by passing through the channel first portions,the elastomeric material deforming to allow the passage through thechannel first portion.

The invention also comprises a bone anchor system comprising a sutureanchor having means thereon for releasable connection to an installationtool; and the installation tool for placing the suture anchor and asuture attached thereto in a bore in a bone, the installation toolcomprising an elongated shroud having an internal opening, and aninserter shaft slidably disposed in the internal opening, the insertershaft comprising a proximal rigid portion connected to a distal flexibleportion, the distal flexible portion being adapted to releasably connectto the suture anchor.

In another form of the invention, the bone anchor system comprises asuture anchor comprising a substantially wedge-shaped body having asmaller distal end and a larger proximal end, means thereon forretaining a suture, and a boundary surface having means thereon forreleasable connection to an inserter shaft; a suture connected to theanchor by the suture retaining means; and an inserter shaft connected tothe anchor by the boundary surface inserter shaft connection means, theinserter shaft comprising an elongated rod having a handle at a proximalend thereof and the anchor disposed at a distal end thereof, the handlebeing generally of a “T” configuration in which the head of the “T” isangled 5°–45° off normal to the axis of the rod, the handle beingconfigured such that the head of the “T” fits a palm of an operator'shand and a portion of the head of the “T” extending outwardly anddistally from the rod proximal end is adapted to receive a thumb of thehand of the operator.

In still another form of the invention, the bone anchor system comprisesa plurality of suture anchors, each comprising a substantiallywedge-shaped body having a smaller distal end and a larger proximal end,means thereon for retaining a suture, and means thereon for releasableconnection thereof to an inserter shaft; an inserter shaft connected toeach of the anchors by the releasable connection means; and a sutureconnected to each of the anchors by the suture retaining means, thesutures each being visually distinguishable from the remainder of thesutures, such that appropriate pairs of strands of the sutures may bevisually identified by an operator.

In yet another form of the invention, the bone anchor system comprises asuture anchor comprising a substantially wedge-shaped body having asmaller distal end and a larger proximal end, means thereon forretaining a plurality of sutures, and means thereon for releasableconnection thereof to an inserter shaft; an inserter shaft connected tothe anchor by the releasable connection means; and a plurality of suturestrands connected to the anchor by the suture retaining means, thesuture strands being visually distinguishable from each other, such thatappropriate pairs of strands of the sutures may be visually identifiedby an operator.

In another form of the invention, the bone anchor system comprises abone anchor having means thereon for retaining a suture; and the sutureretained by the bone anchor; the suture being identifiable by color suchthat the suture can be distinguished from other sutures of other colors.

The present invention also comprises a method for disposing a sutureanchor in a bore in a bone, comprising the steps of:

providing a suture anchor having thereon means for connecting a suturethereto, means for releasably connecting an inserter shaft thereto, abiting edge thereon, and a rounded cam surface on an opposite side ofthe anchor from the biting edge, the inserter connecting means beingoffset from a center of the anchor; and providing an inserter shaftcomprising an elongated rod having a handle at a proximal end thereofand at a distal end thereof connected to the anchor by the releasableconnecting means; and connecting a suture to the anchor by way of themeans for connecting a suture to the anchor;

by manipulation of the inserter shaft, inserting the anchor in the bonewith the biting edge adjacent a first wall portion of the bore in thebone and the rounded cam surface adjacent an opposite second wallportion of the bore;

pulling the inserter shaft so as to cause the rounded cam portion tomove along the second wall portion and the anchor to rotate in the borewith the anchor biting edge biting into the first wall portion of thebore, whereby to lock the anchor in the bore with the suture extendingfrom the bore; and

disengaging the inserter shaft from the anchor.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described with reference to the accompanyingdrawings wherein;

FIG. 1 is a perspective view of a first embodiment of a suture anchoraccording to the invention;

FIG. 2 is an end view of the suture anchor of FIG. 1;

FIG. 3 is a front view of the suture anchor of FIG. 2;

FIG. 4 is an end view of the suture anchor of FIG. 3;

FIG. 5 is a side view of the suture anchor of FIG. 1;

FIG. 6 is a cross-sectional view taken along line 6—6 of FIG. 2;

FIG. 7 is a perspective view of the suture anchor and implantationportion of the first embodiment;

FIG. 8 is a top view of a suture anchor extruded rod blank;

FIG. 9 is a view of the implantation procedure of the present invention;

FIG. 10 is a view of the implantation procedure upon removal of theimplantation device;

FIGS. 11 and 12 show an alternative implantation procedure for thedevice of FIG. 1;

FIG. 13 is a perspective view of an alternative embodiment of the sutureanchor of the present invention;

FIGS. 14 a–d show various embodiments of the plow edge of the device ofthe present invention;

FIG. 15 is a top view of the suture anchor of FIG. 14;

FIG. 16 is a front view of the suture anchor of FIG. 14;

FIG. 17 is a cross-sectional view taken along line 17—17 of FIG. 15;

FIG. 18 is a perspective view of the suture anchor of FIG. 14 with aunitized implantation device;

FIGS. 19 through 22 show the implantation procedure of the sutureanchor;

FIG. 23 is a perspective view of a metal suture anchor according to thepresent invention;

FIG. 24 is a front view of a molded suture anchor according to thepresent invention;

FIG. 25 is a front view of a molded suture anchor according to thepresent invention after implantation;

FIG. 26 is an alternative instrument for implanting the suture anchor ofthe present invention;

FIG. 27 is a front perspective view of an alternative embodiment of thesuture anchor of the present invention;

FIG. 28 is a perspective view of an alternative embodiment of theimplantation device of the present invention with suture anchorattached;

FIG. 29 is a perspective view of the implantation device of FIG. 28;

FIG. 30 is a partial cross-sectional view showing implantation of asuture anchor using the device of FIGS. 28 and 29;

FIG. 31 is a partial cross-sectional view showing implantation of asuture anchor using the device of FIGS. 28 and 29;

FIG. 32 is a partial cross-sectional view showing implantation of asuture anchor using the device of FIGS. 28 and 29;

FIG. 33 is an alternative embodiment of the suture anchor of the presentinvention;

FIG. 34 is a partial cross-sectional view showing implantation of thesuture anchor using the device of FIG. 33;

FIG. 35 is a side view of a suture anchor assembly formed in accordancewith the present invention;

FIG. 36 is a perspective view of the suture anchor assembly shown inFIG. 35;

FIG. 37 is a perspective view of the suture anchor associated with thesuture anchor assembly shown in FIG. 35;

FIG. 38 is a front view of the suture anchor shown in FIG. 37;

FIG. 39 is a sectional view taken along line 39—39 of FIG. 38;

FIG. 40 is an edge view of the suture anchor shown in FIG. 37;

FIG. 41 is a sectional view taken along line 41—41 of FIG. 40;

FIG. 42 is a proximal end view of the suture anchor shown in FIG. 37;

FIG. 43 is a top view of the suture anchor assembly shown in FIG. 35;

FIG. 44 is a side view of the main shaft component of the installationtool associated with the suture anchor assembly shown in FIG. 35;

FIG. 45 is a distal end view of the main shaft shown in FIG. 44;

FIG. 46 is a side view of the shaft tip component of the installationtool associated with the suture anchor assembly shown in FIG. 35;

FIG. 47 is a side view of the nose component of the installation toolassociated with the suture anchor assembly shown in FIG. 35;

FIG. 48 is a sectional view taken along line 48—48 of FIG. 47;

FIG. 49 is a distal end view of the nose shown in FIG. 47;

FIG. 50 is a proximal end view of the nose shown in FIG. 47;

FIG. 51 is a perspective view of the distal end of the shroud componentof the installation tool associated with the suture anchor assemblyshown in FIG. 35;

FIG. 52 is an end view of the shroud shown in FIG. 51;

FIG. 53 is a perspective view showing the suture anchor assembly of FIG.35 in the region where the proximal end of the shroud meets the handlemember of the installation tool;

FIG. 54 is a view of the outside surface of one half of the handle ofthe installation tool associated with the suture anchor assembly shownin FIG. 35;

FIG. 55 is a view of the inside surface of the handle half shown in FIG.54;

FIG. 56 is a view of the outside surface of the other half of the handleof the installation tool associated with the suture anchor assemblyshown in FIG. 35;

FIG. 57 is a view of the inside surface of the handle half shown in FIG.56;

FIG. 58 is a view showing the shaft tip, nose and main shaft of theinstallation tool associated with the suture anchor assembly shown inFIG. 35, with the various components being assembled into asub-assembly;

FIG. 59 is a partial view showing the proximal end of the suture anchorshown in FIG. 37 joined to the distal end of the shaft tip shown in FIG.46;

FIG. 60 is a perspective view of the distal end of the suture anchorassembly shown in FIG. 35, with the assembly's suture element removed;

FIG. 61 is a perspective view showing the distal end of the sutureanchor assembly shown in FIG. 35, with the assembly's suture element inplace;

FIG. 62 is a view showing the suture anchor assembly of FIG. 35 beinggripped by the hand of a user;

FIG. 63 is a side view showing the distal end of the suture anchorassembly of FIG. 35 entering a bore hole formed in a bone;

FIG. 64 is a view showing the distal end of the suture anchor assemblyof FIG. 35 as the suture anchor is being pushed into the bore hole;

FIG. 65 is a view like that of FIG. 64, except showing the suture anchorfully deployed in the bone hole, with the installation tool having beenremoved from the bone;

FIG. 66 is a side view showing an alternative form of suture anchor;

FIG. 67 is a side view showing the suture anchor of FIG. 66 beinginserted into a bore hole;

FIG. 68 is a side view showing the suture anchor of FIG. 66 fully set inthe bore hole;

FIG. 69 is a top end view showing the suture anchor of FIG. 66 disposedin a bore hole;

FIG. 70 is a view of a side of an alternative form of suture anchorformed in accordance with the present invention;

FIG. 71 is a proximal end view of the suture anchor of FIG. 70 disposedin a bore hole;

FIG. 72 is a perspective view showing another form of suture anchorformed in accordance with the present invention;

FIG. 73 is a perspective view showing another form of suture anchorformed in accordance with the present invention; and

FIG. 74 is a perspective view showing another form of suture anchorformed in accordance with the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

A first aspect of a suture anchor according to the present invention isa unitized suture anchor, particularly as shown in FIG. 1. The firstembodiment of the invention will now be described with reference to theFigures. The suture anchor 1 has a first abutment end 2 and a secondabutment end 3. The suture anchor has a substantially cylindricalcross-section as shown in FIG. 2 and the cylindrical longitudinalsurface forms with the abutment end 2 a corner 4. The diameter of thesuture anchor is sized smaller than the bore hole or opening in the bonereceiving the suture anchor. This permits passage of the suture end(s)out of the opening. A suture opening 5 is defined by the body of thesuture anchor 1. In an alternative embodiment shown in FIG. 3 the firstabutment end 2 and second abutment end 3 are slightly tapered to a pointor edge. This is due to the extruding process of formation as will bedescribed below. The suture opening 5 is formed transverse to thelongitudinal direction of the suture anchor 1. Also the suture opening 5is offset from the center of the suture anchor 1 such that an imbalanceis formed in the rotation of the device on implantation as describedbelow.

The suture anchor may be formed either by extrusion or by injectionmolding. When injection molding the suture anchor the implantationstructure of FIG. 7 is preferred. In that Figure it is seen that a shaft6 is formed attached to one end of the suture anchor 1. A thinnedportion forms a frangible portion 7 which will operate to separate thesuture anchor 1 from the shaft 6 upon implantation.

Alternatively, if an extrusion process is used a rod of material isextruded as shown in FIG. 8. Diagonal cuts along cut lines 8 are madeafter boring openings 9 in the rod at predetermined intervals. Thus,each of the suture anchors is formed by the cut severing the suture bodyfrom the suture body of the adjacent anchor.

Now an implantation procedure will be described. With reference to FIG.9 the suture anchor 1 has a suture 10 passed through the opening 5. Anappropriate implantation site is created by, for example, boring a holeof predetermined dimension in the bone material slightly larger than thediameter of the suture anchor. The hole may have a diameter of 5 mm fora suture anchor of 3 mm size and is drilled through the outer cortex ofthe bone into the inner cancellous layer. Upon insertion the sutureanchor is placed within the bore hole by the downward motion as shown inFIG. 9. An upward tug on the shaft portion 6 causes a series of eventsto occur. Initially corner 4 digs into the softer cancellous layer ofthe bone and second abutment end 3 rotates into engagement with theopposite side of the wall. Thus, the anchor is wedged within the openingof the bore hole 11. The shaft 6 separates from the suture anchor 1 bythe breaking of frangible portion 7. This leaves the suture anchor 1implanted within the bone while the shaft 6 is removed. This securelyimplants the anchor within the bone material permitting attachment ofsoft tissue or other materials through the use of suture 10.

An alternative arrangement for implantation is shown in FIGS. 11 and 12.This arrangement may have the suture already in place such that apreloaded anchor and apparatus is provided. The apparatus includes atube 12 which may be formed to receive therein the suture anchor 1. Thesuture 10 is preloaded through the opening 5 defined in the sutureanchor and passed up through the tubular portion to a pull tab 13. Anappropriate bore hole 11 is prepared in the bone and the suture anchorand tube are inserted therein. The suture anchor is permitted to dropout of the tubular portion and becomes slightly dislocated with respectto the tube. End 14 of the tube is cut at a slight angle in order topromote the rotation of the suture anchor in a particular direction. Forexample, as shown in FIGS. 11 and 12, the suture anchor is promoted torotate in a clockwise direction by the longer portion of the tube beingon the left side of the figure, that is the longer side of the sutureanchor. Once the suture anchor has dropped out of the tube 12, the pulltab 13 is used to snug up the suture anchor within the opening. Bypulling upward on the pull tab, the biasing force of the offset holeacting through the pulling force of the suture firmly anchors the suturewithin the opening. At this point, the pull tab may be removed and thesuture slid from within the tubular portion 12.

An embodiment will now be described with reference to FIGS. 13–26. Thesuture anchor 100 has a body 101 formed in a substantially truncatedwedge shape. The body 101 defines a suture opening 102 which is roundedat its openings in order to avoid the likelihood of abrasion to thesuture. An abutment wall 103 may be straight but in the preferredembodiment is provided with a radiused surface which extends in aoblique direction of the anchor. This radius is set to match the radiusof the bore hole into which the anchor is intended to be inserted. Forexample a 4 mm diameter hole would be drilled to receive an anchor witha 4 mm radius to abutment wall 103. A plow wall 104 forms an edge 105 atits intersection with top 106 of the device. The plow wall 104 is alsoradiused in order to maximize contact between edge 105 and the wall ofthe bore hole to improve the action of the corner 105 as both a plow anda frictional engagement mechanism for the anchor.

The corner of edge 105 may be formed in a plurality of manners. Forexample, the edge 105A (FIG. 14A) may be straight and squared off at thejunction between walls 106 and 104, or the edge 105 may be formed with aplurality of teeth 105B to provide additional digging force. Also, theembodiment of FIG. 14B may be modified as shown in FIG. 14C to providebut a single tooth or point which would initiate the digging effect ofthe edge 105C to introduce the remainder of the edge into the softcancellous layer. Finally, an additional alternative embodiment is shownin FIG. 14D wherein the edge 105 is actually a point 105D and the plowwall 104 is actually an edge such that the body of the anchor has asubstantially conical or cylindrical cross section.

FIG. 18 shows a shaft 107 that extends from the top of the suture anchorprior to insertion of the device into the bore hole. The shaft 107 hasformed therein frangible portion 108 in this case formed by a pair ofintersecting webs 109. This structure is preferred in the unitizedinjection molded form of the device as it provides stability between theshaft and suture anchor by maximizing the area moment of inertia of thecross-section while still maintaining a weakness to separationpermitting fracture at the frangible portion by minimizing thecross-sectional area.

A stop 110 is provided in order to locate the device in an insertionapparatus prior to implantation. The entire device is injection moldedout of a polymer material. The angles of junction for the abutment wall103 and the top 106 range from about 60° to about 140° and if preferablyabout 105°. The angle for corner 105 at the juncture of plow wall 104and top 106 ranges from about 20° to about 90° and preferably about 55°.

The anchors of the present invention may be made from eitherconventional bioabsorbable materials or conventional non-absorbablematerials, combinations thereof and equivalents thereof. Examples ofabsorbable materials include homopolymers and copolymers of lactide,glycolide, trimethylene carbonate, caprolactone, and p-dioxanone andblends or other combinations thereof and equivalent thereof. Ofparticular utility are the polylactides, especially poly[L(−)lactide],and the lactide-rich lactide/glycolide copolymers, especially 95/5poly[L(−)lactide-co-glycolide].

Examples of non-absorbable materials from which the suture anchors ofthe present invention may be made include metallic biocompatiblematerials including stainless steel, Nitinol, titanium, Vitalium andequivalents thereof, polymeric materials such as non-absorbablepolyesters, polyamides, polyolefins, polyurethanes, and polyacetals andequivalents thereof.

The bonding of the anchors of the present invention to bone may beadvantageously increased by promoting bone growth. This can beaccomplished by having a microporous surface into which the bone canrapidly grow to aid fixation. This may be particularly advantageous inthe case of a metallic anchor, especially a titanium or titanium alloyanchor, but may also provide benefit in the case of polymeric anchors ofthe present invention, especially those made of absorbable materials.Other methods include the coating of the anchor's surface with asubstance to promote adhesion to the bone. Such coatings include thehydroxyapatite-containing-glass coatings described by Ishikawa, et al.,in the article “Effect of Hydroxyapatite Containing Glass Coating on theBonding between Bone and Titanium Implants” appearing in ClinicalMaterials, Volume 14, 1993, pages 277–285.

It is further noted that the anchors of the present invention can bemade to contain growth factors, especially bone growth factors, that canadvantageously increase the effectiveness of the anchors, especially inthe area of fixation. This may be accomplished in a number of ways,including via coatings or, in the case of absorbable materials, byincorporating the growth factors within the device and allowing them todiffuse out.

The suture anchor devices of the present invention, when made form anabsorbable material, are preferably manufactured by molding usingconventional injection molding equipment and conventional injectionmolding processes. A typical molding process includes the steps of (1)injecting a suitable polymer melt into an appropriately designed mold orcavity at process conditions conventionally employed for such polymersystems, (2) releasing from the mold, after the melt cools in the mold,polymer shaped in the proper configuration to meet the design criteriaof the device. Additionally the anchor molded from the absorbablepolymeric material may be advantageously subjected to an annealingprocess to increase its mechanical or biological performance. Thermalannealing can also be used to increase the dimensional stability ofmolded parts by increasing the crystallinity levels in the parts. One ormore surgical sutures, or one or more sutures with surgical needlesattached, may be used in combination with the suture anchor and may beassembled prior to sterilization. The device can then be sterilizedusing conventional methods to render the anchor suitable for surgicalapplications.

Referring now to FIGS. 19 and 20 the implantation procedure isdisplayed. Referring to FIG. 19 the suture anchor 100 with shaft 107attached thereto is inserted into a bore hole after threading of asuture 111 through suture opening 102. The device is inserted gentlyinto the bore hole until the suture anchor is positioned at a desiredlocation in the hole as shown in FIG. 19. It is generally not desired tobottom out the suture anchor. After insertion of the applier (of thetype in FIGS. 28 and 29), the shaft is drawn upward forcing the edge 105to dig into the softer cancellous layer of the bone. The edge digging inon withdrawal of the shaft creates a rotation of the body of the sutureanchor which, in combination with the withdrawal tension, breaks thefrangible portion 108 and permits removal of the shaft 107 afterseparation. The suture anchor itself rotates fully until abutment wall103 is engaged firmly against the surface of the hole 112 formed in thebone. In this case the corner 105 is formed at about a 40° angle betweenthe top 106 and the plow wall 104. Further, abutment wall 103 and top106 meet to form an angle of about 105°. The top has a length of about4.6 millimeters and the abutment wall has a length of about 3.2millimeters and plow wall 104 has a length of about 3.6 millimeters.These dimensions while specific to this embodimemt are proportional inall sizes of the suture anchor being used. That is, a larger sutureanchor is made by merely proportionally increasing the dimensions whilemaintaining the angular relationship of the sides, walls and top in thesame configuration. As can be seen in FIGS. 21 and 22, this embodimentcan be supplied in a longer version which will require a deeper hole.

An alternative embodiment as shown in FIG. 23 wherein the body 101A isformed of a metal substance such as a titanium alloy. Preferably thealloy is Ti-6A1-4V alloy. The metal body 101A has a similar sutureopening 102 defined therein. An abutment wall 103 and plow wall 104 areprovided as in the polymer version of the device and the plow wall 104forms a corner 105 with the top in a similar fashion. The metal versionis provided with a polymer shaft 107 having frangible portion 108 as isprovided in the previous embodiment. The metal body 101A is insertedinto an injection mold and shaft 107 formed by injection molding theshaft into the metal body 101A. Two intersecting openings are formed toprovide a volume to be filled with polymer. The remainder of the metaldevice is substantially similar to the device of the previousdescription.

The shaft 107 of the metal version of the anchor may be made of anysuitable biocompatible material such as medical grade polymers and maybe a bioabsorbable material such as poly[L(−)lactide].

FIGS. 24 and 25 show the rotational movement of the body 101 of thesuture anchor upon implantation. This rotational movement providestorsional forces to the frangible portion 108 of the shaft 107 topromote the fracture of the shaft at the frangible location.

A novel insertion mechanism is shown in FIG. 26. The applicator 113 hasa screw handle 114 having threads 115 formed thereon. The screw handleis adjusted by rotation against the spring force of spring 116. Oncepositioned, the screw handle is locked in place using locking ring 117,which is threaded down tightly against the back surface of theapplicator 113. A shaft 118 extends from the screw handle 114 along thelength of the applicator 113. The shaft has a wedged end 119 which isreceived substantially within a tubular portion 120 of the applicator.The device may be used in an open procedure. But, tubular portion 120permits optional insertion of the applicator into a trocar forarthroscopic surgery.

The wedged end 119 is extended from within the tubular portion 120 bythe rotation of screw handle 114 to permit extension of the shaft 118and in particular, the wedge end 119 out of the tubular portion 120. Theshaft 107 of the suture anchor is inserted into the tubular portion 120until the stop 110 seats firmly against the tubular portion 120 of theapplicator 113. At this point the screw handle is threaded in theopposite direction in order to draw the wedge end 119 within the tubularportion. The wedging or caming effect of the wedge end 119 firmly graspsthe shaft 107 of the suture anchor and holds it within the device.

A finger 121 extends from the end of tubular portion 120 and seats alongthe top surface of the suture anchor in order to stabilize the body.This prevents premature rotation of the suture anchor and fracture ofthe frangible portion prior to complete insertion. The finger translatesalong the longitudinal portion of the tube in response to motion oftrigger 122. Upon use the device is inserted into a trocar in order toprovide access arthroscopically to the surgical site. The suture anchoris placed into the previously bored bore hole and trigger 122 ismanipulated. The manipulation of trigger 122 moves the finger 121 in thelongitudinal direction. This forces rotation of the suture anchor bodyand promotes the fracture of the frangible portion of the shaft whileholding the anchor in position. Simultaneously with manipulating thefinger 121 the device is withdrawn thus completing the fracture of thefrangible portion of the shaft. The previously threaded suture is thenused to attach soft tissue according to known surgical procedures.

Referring now to FIG. 27, an alternative and preferred embodiment isshown. The body of the suture anchor is shaped as described above,however a mounting opening 130 is provided at one end of the body of thedevice. This opening is sized to receive the mounting end 131 of theinsertion device shown in FIGS. 28 and 29. The insertion device 132having mounting end 131 is comprised of an elongated shaft 133. Theshaft has two sections, a narrower distal section and a wider proximalsection separated by a transitional section 134. The transitionalsection 134 is conical in shape for reasons which will be describedbelow in connection with the implantation procedure. A handle 135 isprovided at a proximal end of the insertion device to facilitategripping of the device during the implantation procedure.

In use, (FIGS. 30 and 31) insertion end 131 is received within mountingopening 130 of the body of the suture anchor as shown in FIGS. 28 and29. Mounting opening 130 is offset from the center line of the body ofthe suture anchor for reasons which will become apparent below. Duringthe insertion procedure the suture anchor is inserted into apreviously-formed bore hole. The insertion tool travels in a positionoff axis from the hole in the bone. Once the transition portion 134reaches the top of the bore hole the transition surface forces theinsertion tool towards the axis of the bore hole (i.e., the transitionportion causes the tool to center). This causes the distal end of thetool to flex slightly and provides additional torque to the sutureanchor assisting the plow edge in digging into the bone. A pair of slots137 are provided to permit the protected passage of the suture out ofthe bore. Upon removal of the insertion tool, (FIG. 32) the flex of thetool forces the plow edge of the suture anchor into the soft cancellousportion of the bone and the distal tip of the insertion tool slips outof the mounting opening 130 due to the upward force provided on theinsertion tool. This provides an extra impetus to the insertion of thesuture anchor and its final implantation and mounting.

In an alternative embodiment the insertion tool may be provided with adistal end 136 of a soft polymer material having therein a stiffeningmember such as a metal wire or polymer of more rigid material. Thus, asoft and manipulable insertion tool is provided having the resilience atthe distal end to provide the insertion forces described above. Thesofter polymer insertion tool aids in producing a friction fit betweenthe distal tip of the insertion tool and the mounting opening 130. Thus,a more sure grip is provided between the tool and the body of the sutureanchor.

In general the mounting opening 130 need not be cylindrical in shape.The mounting opening and distal tip of the insertion tool may be shapedso as to prevent rotation of the suture anchor about the tip.

A further embodiment developed for single piece polymer anchors is shownin FIGS. 33 and 34. The anchor has substantially the same shape as theanchors described above, however a protuberance 138 extends from the topsurface of the wedge. This protuberance has formed therein the mountingopening 130 which receives the insertion tool described above as shownin FIG. 34. This protuberance provides an area for defining the mountingopening 130 such that the opening is not formed within the body of thewedge, possibly weakening the wedge.

Looking next at FIGS. 35 and 36, an alternative and preferred form ofsuture anchor assembly 200 is shown. Suture anchor assembly 200generally comprises a suture anchor 300, an installation tool 400 and asuture 500.

Suture anchor 300 is shown in greater detail in FIGS. 37–42. Sutureanchor 300 comprises a body 301 having a generally wedge-shapedconfiguration. Body 301 comprises a relatively narrow distal end 302terminating in a rounded distal end surface 304, and a relatively wideproximal end 306 terminating in a ledge surface 308 and a protuberance310. An abutment surface 312 extends along a longitudinal axis 314, anda plow surface 316 extends along an intersecting axis 318. Suture anchor300 also comprises a pair of side surfaces 320. As seen in the drawings,abutment surface 312 and plow surface 316 extend between the two sidesurfaces 320 and have a rounded configuration. Preferably this roundedconfiguration is formed so as to have the same radius of curvature asthe bore hole into which the suture anchor is intended to be installed.Plow surface 316 and ledge surface 308 meet in a relatively sharp,well-defined biting edge 322.

Protuberance 310 comprises a substantially flat proximal end surface324, a cam surface 326 extending between abutment surface 312 andproximal end surface 324 and a transition surface 328 extending betweenledge surface 308 and proximal end surface 324. As seen in the drawings,cam surface 326 is curved along its length. Cam surface 326 can beformed with a relatively constant radius of curvature throughout itslength or, alternatively, cam surface 326 can be formed so as to have achanging radius of curvature when progressing distally to proximallyalong its length, for reasons which will be hereinafter discussed. Byway of example, cam surface 326 can be formed so as to have aprogressively increasing, or a progressively decreasing, radius ofcurvature when progressing distally to proximally along its length.

The suture anchor's ledge surface 308, transition surface 328, andproximal end surface 324 together form a complete boundary surface 329.

A through-hole 330 extends across suture anchor 300, from one sidesurface 320 to the other. Through-hole 330 is sized so as to have adiameter somewhat larger than the diameter of suture 500, whereby suture500 can be slipped through through-hole 330, as will hereinafter bediscussed in further detail. If desired, through-hole 330 can be sizedso as to have a diameter somewhat larger than the combined diameters oftwo or more sutures, whereby several sutures can be simultaneouslyslipped through through-hole 330. Preferably the entryways tothrough-hole 330 are rounded somewhat as shown at 332 so as to provide asmooth transition between side surfaces 320 and through-hole 330. Such aconfiguration assists initial passage of suture 500 through through-hole330, as well as facilitating subsequent slipping motion of the suturerelative to the suture anchor, e.g., such as when the suture anchor isdeployed in a bone. In addition, such a configuration helps distributethe suture bearing stress more uniformly throughout the contour ofthrough-hole 330.

A blind hole 334 opens on the suture anchor's proximal end surface 324and extends distally into the suture anchor along an axis 336. Blindhole 334 serves as a mounting opening to receive the distal end ofinstallation tool 400, as will hereinafter be discussed. Blind hole 336is disposed closer to abutment surface 312 than to biting edge 322. Axis336 is preferably set at a slightly intersecting angle relative to thelongitudinal axis 314 of abutment surface 312. Preferably the axis 336of blind hole 334 is set at an angle of about 1° relative to thelongitudinal axis 314 of abutment surface 312, although this angle maybe varied as preferred. Blind hole 334 comprises a bore 338 and acounterbore 340. Bore 338 and counterbore 340 meet at an annularshoulder 342.

Suture anchor 300 can be formed using any of the materials and/ortechniques hereinabove discussed in connection with any of the anchorshereinabove discussed, or it can be formed using any other appropriatebiocompatible material or technique. In one preferred form of theinvention, suture anchor 300 is formed out of a bioabsorbable materialsuch as polylactic acid (PLA).

Looking next at FIGS. 35 and 43, installation tool 400 generallycomprises a main shaft 402, a shaft tip 404, a nose 406, a shroud 408,and a handle 410.

Main shaft 402 is shown in greater detail in FIGS. 44 and 45. Itcomprises a substantially rigid elongated rod having a distal end 412terminating in a distal end surface 414, and a proximal end 416terminating in a proximal end surface 418. A blind hole 420 is formed inthe distal end of the shaft, extending proximally from distal endsurface 414. Blind hole 420 is used to connect main shaft 402 to shafttip 404, as will hereinafter be discussed. A plurality ofcircumferentially-extending surface grooves 422 are formed in theproximal end of main shaft 402, just distal to proximal end surface 418.Surface grooves 422 provide the proximal end of main shaft 402 with acontour, and are used to connect main shaft 402 to handle 410, as willalso hereinafter be discussed.

Shaft tip 404 is shown in greater detail in FIG. 46. It comprises arelatively short rod having a distal end 424 and a proximal end 426.Distal end 424 is formed so as to be somewhat flexible, and terminatesin a threaded portion 428 comprising a plurality of screw threads 430.The crests of screw threads 430 have substantially the same diameter asthe adjoining portion 432 of shaft tip 404, which diameter is slightlylarger than the diameter of the suture anchor's bore 338 but slightlysmaller than the diameter of the suture anchor's counterbore 340, forreasons which will hereinafter be discussed. The total length of theshaft tip's threaded portion 428 is sized to be approximately the sameas the distance between the suture anchor's shoulder 342 and the base ofblind hole 334. A circumferentially-extending surface groove 434 isformed in proximal end 426 of shaft tip 404, just distal to proximal endsurface 436. A flange 438 is disposed intermediate shaft tip 404. Flange438 provides a distally-facing shoulder 440 and a proximally-facingshoulder 442.

Shaft tip 404 can be formed out of any appropriate biocompatiblematerial. By way of example, in one preferred form of the invention,shaft tip 404 is formed out of 17-4 PH stainless steel.

Nose 406 is shown in greater detail in FIGS. 47–50. Nose 406 comprises agenerally frustoconical body 444 terminating in a distal end surface 446and a proximal end surface 448. An axial hole 450 opens on, and extendsbetween, distal end surface 446 and proximal end surface 448. A pair ofposts 452 extend proximally out of the nose's proximal end surface 448.A pair of diametrically-opposed surface grooves 454 extend betweendistal end surface 446 and proximal end surface 448 in the manner shownin the drawings.

Shroud 408 is used to retain suture 500 on installation tool 400 untilthat suture is to be deployed at the surgical site. Shroud 408 is shownin greater detail in FIGS. 51–53. It comprises a relatively flexiblebody terminating in a distal end surface 456 and a proximal end surface458. The shroud's body has a generally four-sided configuration,including a pair of diametrically-opposed sides 460, forming ridgeportions, and a pair of diametrically-opposed sides 462. Anelliptically-shaped internal opening 464 opens on, and extends between,distal end surface 456 and proximal end surface 458. Internal opening464 is arranged so that its long axis is aligned with the shroud's sides460, while its short axis is aligned with the shroud's sides 462.Internal opening 464 is sized so the installation tool's main shaft 402can be received within internal opening 464, with main shaft 402 makinga close sliding fit across the internal opening's short axis, as willhereinafter be discussed in further detail.

Each of the shroud's sides 462 includes a longitudinally-extendingchannel 466. Each of the channels 466 communicates with the regionexternal to the shroud via a corresponding longitudinally-extending slot468. Channels 466 are preferably sized so as to have a diameterapproximately the same as the diameter of suture 500, while slots 468are sized so as to have a width somewhat less than the diameter ofsuture 500. Each of the shroud's sides 462 is recessed or scalloped away(as at 470) for a short length near the proximal end of the shroud so asto open the full diameter of each of the channels 466 to the regionexternal to the shroud.

Shroud 408 may be formed out of any appropriate material, e.g., it maybe formed out of a soft compliant polymer such as nylon orpolypropylene.

It is to be appreciated that, on account of the foregoing construction,(i) by pressing on the shroud's opposing ridge portions (i.e., sides460), slots 468 can be made to widen so as to permit suture 500 to belaid down in channels 466, and (ii) by relaxing pressure on the shroud'sopposing sides 460, slots 468 can be made to return to their normal,narrower width so as to retain suture 500 in channels 466. It is also tobe appreciated that, inasmuch as shroud 408 is formed out of arelatively flexible material, any suture 500 disposed in channels 466can be pulled free of the channels with an appropriate withdrawal force,whereby the suture can be freed from the installation tool. Inparticular, suture 500 can be freed from installation tool 400 bypulling the suture in an axial direction relative to the installationtool, whereby the suture will be drawn out of the ends of channels 466;or suture 500 can be freed from installation tool 400 by pulling thesuture at an angle to the installation tool, whereby the suture will bepeeled out of channels 466 via a deformation of slots 468.

Looking next at FIGS. 35, 43 and 54–57, handle 410 is preferably formedout of two halves 410A and 410B which are attached together so as toform the complete handle 410. Handle 410 comprises a contoured recess472 (which is in turn formed out of contoured hemi-recesses 472A and472B) which is configured so as to make a tight fit about thecorrespondingly contoured proximal end of main shaft 402, whereby handle410 can be securely mounted to main shaft 402 and thus used tomanipulate installation tool 400. The exterior configuration of handle410 includes a first protrusion 474, a second protrusion 476 and a thirdprotrusion 478. First protrusion 474 is aligned with the installationtool's main shaft 402 along an axis 480 (FIG. 35). Second and thirdprotrusions 476 and 478 are aligned with one another along another axis482. Axis 482 is set an inclined angle relative to axis 480. Preferably,axis 482 is set at an angle of about 70° 0 (as measured along the arc484 in FIG. 35), although angles of about 45° to about 85° are alsoappropriate. Thus, first, second, and third protrusions 474, 476 and 478form an inclined “T” configuration. Second and third protrusions 476 and478 are sized so that they will together form a natural handle for auser, e.g., so that the user's thumb and forefinger can comfortablyengage second protrusion 476 while the user's remaining fingers engagethird protrusion 478. As a result of the foregoing construction, theuser will be able to comfortably grasp the installation tool's handle410 and, with the pad of the hand engaging the handle's proximal surface486, thereafter thrust the installation tool distally along the axis480, as will hereinafter be discussed.

Suture anchor assembly 200 is intended to be assembled as follows.First, installation tool 400 is assembled, then suture anchor 300 isattached to the assembled installation tool, and finally suture 500 isattached to suture anchor 300 and installation tool 400.

Installation tool 400 is intended to be assembled as follows.

First, main shaft 402, shaft tip 404 and nose 406 are assembled into asubassembly such as shown in FIG. 58. This is done by mounting nose 406on shaft tip 404 by inserting the proximal end of the shaft tip throughaxial hole 450 of the nose until the shaft tip's proximally-facingshoulder 442 engages the nose's distal end surface 446, and thenmounting shaft tip 404 on main shaft 402 by inserting the proximal endof the shaft tip in the main shaft's blind hole 420 until the mainshaft's distal end surface 414 engages the nose's proximal end surface448. The proximal end of shaft tip 404 is made fast in main shaft 402 bycrimping or by other means well known in the art. As a result of theforegoing construction, nose 406 is effectively captured between theshaft tip's proximally-facing shoulder 442 and the main shaft's distalend surface 414.

Next, shroud 408 is loaded onto the aforementioned subassembly. This isdone by first aligning main shaft 402 with the shroud's internal opening464, with the two posts 452 of the nose being aligned with the long axisof the elliptically-shaped opening 464. Then the proximal end of mainshaft 402 is passed through the shroud's internal opening 464 until thetwo posts 452 of the nose enter the shroud's internal opening 464 andthe shroud's distal end surface 456 seats firmly against the nose'sproximal end surface 448. At this point each of the two surface grooves454 of nose 406 will be aligned with one of the channels 466 of shroud408, with main shaft 402 making a close sliding fit across the shortaxis of the shroud's internal axis 464.

Next, handle 410 is attached to the proximal end of main shaft 402. Thisis done by fitting the proximal end of main shaft 402 in eitherhemi-recess 472A of handle half 410A or hemi-recess 472B of handle half410B, and then placing the corresponding complementary second handlehalf (i.e., either handle half 410B or handle half 410A, respectively)in place, and finally making the two handle halves fast to one anotherin ways well known in the art (e.g., by ultrasonic welding), wherebythey will be securely attached to the proximal end of main shaft 402. Itis to be appreciated that when handle 410 is so mounted to main shaft402, the distal end of the handle's first protrusion 474 willsubstantially engage the shroud's proximal end surface 458. It is alsoto be appreciated that handle 410 is mounted to main shaft 402 such thatthe plane extending between the two handle halves 410A and 410B will bealigned with the major axis of the shroud's internal opening 464, withone of the shroud's channels 466 being aligned with each handle half,and with the one of the shroud's recessed or scalloped sections 470being aligned with, and residing adjacent to, each handle half.

It is to be appreciated that inasmuch as main shaft 402 and shaft tip404 are formed out of two separate elements which are securely attachedtogether, each element can be designed for its own particularrequirements. In particular, main shaft 402 can be designed so as toprovide the desired rigidity, whereas shaft tip 404 can be designed soas to provide the desired flexibility; yet the two elements are securelyattached to one another so as to together operate as the desired unit.

Suture anchor 300 is attached to the assembled installation tool 400 asfollows. First, suture anchor 300 and installation tool 400 are orientedso that the distal end of shaft tip 404 is aligned with the sutureanchor's blind hole 334. Then suture anchor 300 and installation tool400 are brought together as they are simultaneously turned relative toone another, whereby the suture anchor will be mounted on the distal endof the installation tool's shaft tip 404, with the threaded portion 428of shaft tip 404 being threadedly mounted in the suture anchor's bore338, and with the immediately-proximal portion 432 of the shaft tipbeing received in the suture anchor's counterbore 340. It is to beappreciated that due to the relative sizing of the suture anchor's blindhole 334 (see FIG. 59) and the shaft tip's distal end 424, the shafttip's threaded portion 428 will make a threaded engagement with thesuture anchor within bore 338, but the shaft tip's immediately-proximalportion 432 will not be secured to the suture anchor within counterbore340.

Suture anchor 300 and installation tool 400 are arranged so as to have aspecific orientation relative to one another, i.e., so that the sutureanchor's two side surfaces 320 extend parallel to the plane extendingbetween the two handle halves 410A and 410B, with the suture anchor'sabutment surface 312 being aligned with the handle's second protrusion476 and the suture anchor's plow surface 316 being aligned with thehandle's third protrusion 478 (see FIGS. 35, 36 and 60). It is to beappreciated that, on account of the foregoing arrangement, the user willalways know the orientation of suture anchor 300 simply by knowing theorientation of the installation tool's handle 410. This can be animportant feature in certain types of surgery where the suture anchormay have to be set with a particular orientation and the user's view ofthe suture anchor itself may be restricted.

Next, suture 500 is attached to suture anchor 300 and installation tool400. This is done by passing suture 500 through the suture anchor'sthrough-hole 330 and then positioning the suture within the shroud'slongitudinally-extending channels 466. In this respect it will beappreciated that suture 500 can be easily positioned in channels 466 byfirst pressing on the shroud's opposing side surfaces 460 so as to openslots 468, then laying down suture 500 within the opened channels 466,and then releasing the shroud's opposing side surfaces 460 so as toreleasably capture the suture within channels 466. The proximal ends ofsuture 500 are arranged so that they exit the shroud adjacent torecessed or scalloped portions 470, where they rest free adjacent tohandle 410 (see FIGS. 36, 53 and 61).

Suture anchor assembly 200 is intended to be used as follows.

First, suture anchor assembly 200 is picked up by the user so that theuser's thumb and forefinger engage the handle's second protrusion 476and the user's remaining fingers engage the handle's third protrusion478, and so that the handle's proximal surface 486 sits against the heelof the user's hand (see FIG. 62). It is to be appreciated that when thesuture anchor assembly is held in this manner, the apparatus will beready to drivingly insert the suture anchor in a bore hole formed in abone. Furthermore, in view of the fact that the suture anchor is mountedto the installation tool with a predetermined orientation, the user willalways know the relative positioning of the suture anchor's abutmentsurface 312, its plow surface 316, and its sharp, well-defined bitingedge 322, even if the suture anchor itself is not directly visible tothe user.

Next, the user uses installation tool 400 to drive suture anchor 300into a bore hole. This is done by aligning suture anchor 300 with a borehole 600 formed in a bone 601 (FIG. 63) and then pushing the sutureanchor into the bone hole. As this occurs, the suture anchor's plowsurface 316 will first tend to engage rim 603 of bore hole 600, causingthe distal end of shaft tip 404 to flex as the suture anchor pivots toenter the bore hole. Further downward pressure on the installationtool's handle 410 causes the distal end of the shaft tip to flex evenfurther as the suture anchor's plow surface 316 engages, and then ridesalong, wall 602 of the bore hole, with the suture anchor's cam surface326 being slightly spaced from, or insignificantly in contact with, thebore hole's opposing wall 606 (see FIG. 64). Significantly, such flexingof the distal end of shaft tip 404 does not significantly undermine theattachment of suture anchor 300 to installation tool 400, since only thedistalmost portion of the shaft tip (i.e., the threaded portion 428) isactually secured to the suture anchor, with the shaft tip'simmediately-proximal portion 432 being free to flex slightly within thesuture anchor's counterbore 340 without damaging the suture anchor. Thisis true even where suture anchor 300 may be formed out of a non-metallicmaterial, e.g., a plastic or absorbable material.

The user pushes suture anchor 300 downward into bore hole 600 until thedesired depth is reached. Such downward pressure keeps the sutureanchor's plow surface 316 in engagement with the bore hole's wall 602.Preferably installation tool 400 is sized so that nose 406 engages thetop surface 604 of bone 601 when the desired depth is reached.

Next, the user withdraws installation tool 400 from bore hole 600. Asdownward pressure on installation tool 400 is released (to be replacedby opposite upward pressure during tool withdrawal), the flexed shafttip 404 tries to straighten itself, causing the suture anchor's sharp,well-defined biting edge 322 to press into wall 602, and causing thesuture anchor to pivot slightly in the bore hole so that the sutureanchor's cam surface 326 securely engages wall 606 of the bore hole. Asthe user retract's installation tool 400 from bore hole 600, rearwardmovement of installation tool 400 causes progressively more distalportions of the suture anchor's cam surface 326 to come into engagementwith wall 606 of the bore hole. Since cam surface 326 is arranged to camthe suture anchor laterally, such engagement of cam surface 326 withbone wall 606 causes the anchor's sharp, well-defined biting edge 322 tobe driven progressively further and further into wall 602 of the borehole, until the suture anchor's abutment surface 312 rests against wall606 (FIG. 65). As installation tool 400 is pulled further back, theinstallation tool eventually breaks free from the lodged suture anchor.The installation tool is then withdrawn from the surgical site.

It should be appreciated that the presence of cam surface 326significantly enhances the ability of suture anchor 300 to set in bone601, since the cam surface provides a force on the suture anchor's edgesurface 322 which is approximately normal to the bore hole's wall 602.This force drives the suture anchor's edge surface 322 into wall 602,ensuring that the suture anchor will be reliably set. This is true evenwhere bone 601 is relatively hard (e.g., cortical bone) and the sutureanchor is made out of a non-metallic material, e.g., plastic or abioabsorbable material.

By changing the geometry of cam surface 326, the setting characteristicsof suture anchor 300 can be adjusted.

It should also be appreciated that the nature of the attachment ofsuture anchor 300 to installation tool 400 is important. In particular,the suture anchor must be attached to the installation tool securelyenough to cause the suture anchor to turn in the aforementioned cammingaction, yet release at the appropriate time so as to leave the sutureanchor in the bone as the installation tool is withdrawn. Thus it isdesirable that the connection between suture anchor 300 and installationtool 400 be well defined at the time of manufacture, and remain intactup until the time that the installation tool breaks free from theanchor. In particular, it is important that this connection not beundermined while the distal end of the installation tool flexes in thebore hole. It has been found that such a reliable connection can beestablished by providing the distal end of the shaft tip with a threadedportion 428 and an immediately-proximal smooth portion 432, andproviding suture anchor 300 with a bore 338 and a counterbore 340, wherethe shaft tip's threaded portion 428 makes a threaded engagement withthe suture anchor within bore 338, but the shaft tip'simmediately-proximal portion 432 is not secured to the suture anchorwithin counterbore 340. This permits the necessary flexing of the shafttip to occur without undermining the connection between the installationtool and the suture anchor, even where the suture anchor is formed outof a non-metallic material, e.g., a plastic or absorbable material.

It is to be appreciated that as installation tool 400 separates from thedeployed anchor 300, suture 500 can simultaneously slide along the innersurfaces of the shroud's channels 466, so as to permit the two membersto separate. Depending on the length of suture 500 and the degree ofseparation imposed, suture 500 may or may not be fully removed frominstallation tool 400 during anchor deployment. To the extent that someof suture 500 remains attached to installation tool 400 after theinstallation tool has been withdrawn, the installation tool may beplaced on a surgical drape adjacent to the surgical site until thesuture 500 is to be completely removed from the installation tool. Atthat point the remaining suture may be pulled free of the installationtool.

For many procedures, retaining a portion of suture 500 in installationtool 400 until needed can be helpful for effective suture management.For example, where an arthroscopic procedure involves more than onesuture anchor, the paired suture ends of several suture anchors mightemanate from a single cannula opening. By way of example, anarthroscopic Bankhart procedure could involve four or even six suturelengths emanating from a single cannula opening. In such a situation,retaining suture lengths in the installation tool can help keep thesuture lengths more easily identifiable for the surgeon.

Additionally, and/or alternatively, to help improve suture management,it may be desired to mark various suture lengths. For example, eachsuture length could be distinctively color-coded, or distinctivelypattern-coded. U.S. Pat. No. 3,949,755 issued Apr. 13, 1976 to Vauquoisteaches the provision of contrasting shades on suture, which patent ishereby incorporated herein by reference.

It is also possible to modify the suture anchor 300 described above.

For example, in the suture anchor 300 described above, the sutureanchor's through-hole 330 is preferably sized so as to slidably receivea single strand of suture. However, if desired, the suture anchor'sthrough-hole 330 could be sized so as to slidably receive multiplestands of suture simultaneously. Of course, if such a construction wereused, the shroud's channels 466 should be correspondingly enlarged so asto accommodate the additional suture lengths provided, or some otherprovision should be made to manage the additional suture ends presentwith such a construction.

Furthermore, with the suture anchor 300 described above, the sutureanchor's through-hole 330 is formed so as to have a substantially roundconfiguration. However, the suture anchor's through-hole can also beformed with an elliptical configuration, such as the through-hole 330Aprovided in the suture anchor 300A shown in FIGS. 66–68. By forming thesuture anchor's through-hole with an elliptical configuration, stressesfrom the suture can be directed to specific portions of the sutureanchor. In particular, these suture stresses can be directed to morerobust portions of the suture anchor, thereby enabling the suture anchorto carry larger loads. This feature can be particularly useful where thesuture anchor is formed out of a non-metallic material, e.g. a plasticor bioabsorbable material. In addition, by forming the suture anchor'sthrough-hole with an elliptical configuration, subsequent proximalpulling of the suture can also help to further set the suture anchorwith a desired orientation within the bone.

Also, with the suture anchor 300 described above, the suture anchor isconfigured so as to have substantially planar side surfaces 320. As aresult, the anchor must be formed thin enough so that the suture lengthsemanating from the anchor can pass alongside the suture anchor withinthe bore hole (see FIG. 69). This is particularly true where it isdesired to slide suture 500 relative to suture anchor 300 when thesuture anchor is set in a bone hole. However, in many situations it canbe advantageous to form the suture anchor with the thickest possibleconfiguration, with the sides of the suture anchor having a roundedouter surface, e.g., such as the side surfaces 320B provided for thesuture anchor 300B shown in FIGS. 70 and 71. In this situation, apathway 344 must be provided to permit suture 500 to pass from thesuture anchor's through-hole 330 to the exterior of the bone. In thisrespect it should also be appreciated that inasmuch as the suture anchormust rotate within the bone, the pathways 344 should be formed with aconfiguration which broadens toward the proximal end of the anchor, inthe manner schematically illustrated in FIG. 70. Such a constructionpermits the necessary anchor rotation to occur without causing thesuture to come into abrasive engagement with the side walls of the borehole.

Also, it is possible to omit the suture anchor's through-hole 330 andattach the suture directly to the anchor. Thus, for example, a sutureanchor 300C is shown in FIG. 72 where the suture 500 is molded or fuseddirectly into the side 320C of the body of the anchor. Alternatively,and looking now at FIG. 73, the suture 500 could enter the proximal endsurface 324D of a suture anchor 300D and then be internally fused to theinterior of the suture anchor. This could be done with a single suturestrand, or with a pair of independent suture strands, or with a loopedsuture strand where the loop is fused within the interior of the body.

It is also possible to attach a suture to the suture anchor by forming alongitudinal hole through the suture anchor, passing the suture throughthat longitudinal hole, and then knotting the suture at the distal endof the suture anchor so as to prevent the suture from being withdrawnproximally through the suture anchor. Alternatively, an enlargement ofsome other sort could be positioned at the distal end of the suture toprevent suture withdrawal. Thus, for example, a suture anchor 300E isshown in FIG. 74, wherein suture 500 passes through a pair oflongitudinal holes 346 opening on proximal end surface 324D, and thenare knotted at a knot 502 near the distal end of the anchor. If desired,a recess or cutaway 348 can be provided near the distal end of theanchor to accommodate knot 502. Alternatively, a single suture strand500 could be used, with the suture strand passing down one longitudinalhole 346 and back up the other longitudinal hole, whereby the use of theknot 502 could be eliminated.

Thus, the invention has been described with reference to the attacheddrawings. It is easily understood by one of ordinary skill in the artthat changes may be made to the embodiments described herein withoutexceeding the spirit or scope of the attached claims.

1. A method for disposing a suture anchor in a bone, the methodcomprising the steps of: providing a suture anchor comprising agenerally wedge-shaped configuration defined by a ledge surface at afirst end thereof, a protuberance upstanding from the ledge surface, anabutment surface depending from the protuberance, a rounded cam surfacedefined by a juncture of the protuberance and the abutment surface, anda plow surface depending from the ledge surface and angled toward theabutment surface to form therewith a rounded distal end surface, theplow surface and the ledge surface defining a biting edge, theprotuberance being provided with a recess off-set from a center of theanchor first end, the anchor further being provided with a through-holeextending therethrough from side to side; providing an insertercomprising a shaft having a tip portion, and a handle; releasablymounting the suture anchor on the inserter shaft tip portion by engagingthe protuberance recess with the inserter shaft tip portion; extending asuture through the anchor through-hole; by manipulation of the inserter,inserting the anchor, distal end surface first, into a bore in the boneuntil the biting edge is adjacent a first wall portion of the bore, andthe cam surface is adjacent an opposite second wall portion of the bore;pulling the inserter to cause the cam portion to move along said secondwall portion and the anchor to rotate in the bore, and the biting edgeto bite into said bore first wall portion, to bind the anchor in thebone bore with the suture extending from the bore; and releasing theanchor from the shaft tip.